The purpose of this study is to conduct a scientometric analysis of the global climate change (GCC) literature to identify the patterns, trends and biases in this research field. Data were obtained using the Thomson ISI database. A total of 5,444 articles on GCC were recorded, showing a temporal increase in the number of articles (r = 0.84; P < 0.0001). Most the articles look at the impact of climate change on geophysical variables, humans and vegetation. Few studies look at fungi, amphibians or reptiles (H = 24.6; P < 0.0001, N = 27). Principal component analysis revealed a temporal difference in the keywords associated with each article. In the first years we observed that the most frequent keywords indicated worry about the main causes of global climate change, but this shifted in more recent years towards keywords indicating concern with the effects of climate change on biodiversity. We argue that this scientometric study can help guide future climate change research and contribute to our understanding of several poorly studied areas.

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In this study, we determined the temporal trends of publications by Brazilian authors on phytoplankton and compared these trends to those of other Latin American countries as well as to the 14 countries ranking ahead of Brazil in terms of scientific publication. To do this, we investigated phytoplankton studies published in an international database (Thomson-ISI). The data showed that Brazil plays an important role among other Latin American countries in the publication of these studies. Moreover, the trend of studies published on phytoplankton in Brazil was similar to trends recorded in the developed countries of the world. We conclude that studies can be more deliberately targeted to reduce national and international asymmetries by focusing on projects with large spatial scales and projects that concentrate on less-studied geographic regions, thus encouraging increased productivity in remote areas of the country. Associated with this is a necessary increase in high-impact journal publications, increasing the quantity and quality of Brazilian scientific studies on phytoplankton and, consequently, their global visibility.Keywords: Brazil, global rating, latin america, scientometrics. Produção científica brasileira sobre estudos fitoplanctônicos: determinantes nacionais e comparações internacionais ResumoEsse estudo teve por objetivo determinar a tendência temporal das publicações sobre fitoplâncton de autores brasileiros e comparar essa tendência com outros países latino-americanos, bem como aos 14 principais países em termos de publicação científica. Para isso, investigou-se artigos sobre fitoplâncton disponível em uma base de dados internacionais (Thomson-ISI). A tendência da produção científica de autores brasileiros foi superior a maioria dos países latinoamericanos. Além disso, essa tendência foi similar ao dos países desenvolvidos do mundo. Conclui-se que futuros estudos devem buscar reduzir as assimetrias nacionais e internacionais, concentrando trabalhos em grandes escalas espaciais e em regiões geográfica menos estudadas, incentivando assim, o aumento da produtividade em áreas remotas do país. Associado a isso, destaca-se a importância de aumento de publicações de brasileiros em revistas de alto impacto, aumentando a quantidade e qualidade dos estudos científicos brasileiros sobre o fitoplâncton e, consequentemente sua visibilidade internacional.Palavras-chave: Brasil, taxa global, américa-latina, cienciometria.

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Chlorophyll-a (Chl-a) has been widely used in the assessment and monitoring of aquatic environments. Local and regional factors can influence Chl-a concentrations; moreover, the connection between terrestrial and aquatic ecosystems is a major paradigm within aquatic ecology. Here, we investigate the spatial distribution of Chl-a concentrations in a tropical savannah floodplain in Central Brazil using a broad spatial data set (a 900-km north-south transect; 30 lakes). We determine the relative importance of local environmental variables (limnological and morphometric) and regional (land use) and spatial distances (spatial eigenvector) on Chl-a concentrations using partial linear regression. We evaluate the direct and indirect effects of local and regional variables on Chl-a with a path analysis. Our results indicate spatially autocorrelated patterns wherein lakes in closer proximity showed more similar levels of Chl-a than more distant lakes. Local environmental factors explained most variance in Chl-a (R = 0.28; P = 0.02); more specifically, both lake area and total nitrogen significantly (P< 0.05) explained Chl-a concentrations (direct effects). Meanwhile, regional factors neither directly nor indirectly predicted Chl-a. Thus, internal processes, such as the resuspension of sediment (which is frequent in tropical floodplains), rather than external influences, were the main factors that explained Chl-a concentrations in this study. The importance of local variables in structuring Chl-a concentration may be used to guide the conservation of the aquatic ecosystems in these tropical floodplain lakes.